Ewan McGregor is a journalist assigned to rewrite the memoirs of a former British prime minister in Roman Polanski's latest "The Ghost Writer."Ewan McGregor plays a writer who tackles and difficult — and possibly deadly — assignment.

"The Ghost Writer” is a deviously intriguing thriller about a
British politician, his brittle brilliant wife and a strictly-for-hire
memoirist who finds out more about his subject than he’d bargained for.

It is also a film by Roman Polanski.

The Ghost Writer

(PG-13) Summit (126 min.)Directed by Roman Polanski. With Ewan McGregor, Pierce Brosnan, Olivia Williams. Now playing in New York.

That second sentence is, unfortunately, why many people won’t be reading this one; they’ve already muttered “pervert” and turned the page, reiterating their determination to never give the jailed director one more dime.

And I understand that.

Yet it’s not a stance that I, as a film critic, can really adhere to. Nor, as a film fan, would I really want to. Cinema is full of great artists who were also horrendous people. As long as they could keep their horrendous ideas off screen, the art remained great.

Polanski’s “The Ghost Writer” is not an apologia for what he did (although a very close look shows a few interesting themes). It’s a brilliantly made, paranoid, leftish political thriller. And it’s also the first great film of the year.

The story revolves around a hungry hack, played by Ewan McGregor, given an impossible assignment. They’re the lengthy memoirs of a recent, very slick prime minister (played with a wolfish grin by Pierce Brosnan), they’re due in a month and they’re a mess.

Also, the last ghost writer died under mysterious circumstances.

“The Ghost Writer” is going to be called Hitchcockian by viewers who focus on the tricky plot and the lush score by Alexandre Desplat. But it isn’t, really. In fact, the adjective it really deserves is one we haven’t heard in a while: Polanski-esque.

Right from his first films in Poland, Polanski’s best movies were marked by a wry absurdism, convinced of nothing but looming, unavoidable disaster. And the bitterest gag was that the heroes — sometimes played by Polanski himself — were never in on the joke.

And so, in “The Ghost Writer,” McGregor arrives at some fabulous borrowed mansion to try to get a peek behind Brosnan’s carefully constructed façade. But what McGregor thinks he sees isn’t real. And what he doesn’t see could be fatal.

McGregor is fine as the writer, although frankly he projects a bit too much handsome confidence. Then again, part of the hack’s problem is that he thinks he knows exactly what’s going on — just as part of the Brosnan character’s power is that he fervently believes his own lies.

Wonderful, too, is Olivia Williams as Brosnan’s long- (but not silently) suffering wife. Unrecognizable from her mousy teacher in “An Education,” she’s a sexy cipher who makes every scene a veritable acrostic of hidden agendas and secret disappointments.

The couple is not — oh no, certainly not — to be confused with Tony and Cherie Blair. Nor should “The Ghost Writer” be confused with the unrelated Philip Roth novel — or, perhaps, with previous Polanski masterpieces like “Repulsion” or “The Pianist.”

It’s a slick conspiracy thriller, and part of the reason it stands out is that — judging by recent films like “State of Play” or “Edge of Darkness” — Hollywood no longer knows how to make them. (Interestingly, like those films, “The Ghost Writer” is also based on a previous English work, in this case a novel by Robert Harris.)

Polanski knows how the genre works, though. He knows it’s not the raving lunatics who frighten, but the only slightly “off” normal people — a gardener, a cook, a chauffeur. He realizes it’s not what you see that’s horrifying, but what you don’t. (The film’s last moments — its best — center on something that happens off-screen.)

Darkly dramatic, “The Ghost Writer” is Roman Polanski’s most accessible film since “Chinatown.” And when you really look at its themes — public faces, private lies, media frenzies and celebrity self-pity — it may be even more relevant than its audiences, and its director, realize.

Unfortunately, because it’s a “Roman Polanski film,” those audiences may not see it. And, ironically, because he’s Roman Polanski, the director may never really see why.